Air actuated apparatus for controlling the diameter of a cigarette rod



Nov. 11, 1969 c. s. MCARTHUR 3,477,441

AIR ACTUATED APPARATUS FOR CONTROLLING THE DIAMETER OF A CIGARETTE ROD Filed May 51, 1968 2 Sheets-Sheet l Z2 INVENTOR. COL/N 5. MC/QPTHUR Tic. E. a )k w 4 TTORNE Y Nov. 11, 1969 c. s. MCARTHUR AIR ACTUATED APPARATUS FOR CONTROLLING THE DIAMETER OF A CIGARETTE ROD 2 Sheets-Sheet 2 Filed May 31, 1968 United States Patent AIR ACTUATED APPARATUS FOR CONTROLLING THE DIAMETER OF A CIGARETTE ROD Colin S. McArthur, Winston-Salem, N.C., assignor to R.. J. Reynolds Tobacco Company, Winston-Salem,

N.C.,' a corporation of New Jersey Filed May 31, 1968, Ser. No. 733,390 Int. Cl. A24c /18 US. Cl. 131-21 7 Claims ABSTRACT OF THE DISCLOSURE An apparatus for monitoring and controlling rod diameter in a cigarette or filter rod machine by pneumatically measuring rod diameter as it is formed, amplifying and mechanically applying the pneumatic measurement to adjustably raise or lower the folder block andthereby vary rod diameter. A fluid actuated mechanism is mechanically connected to the folder block and is also connected to the amplifier. The fluid actuated mechanism mechanically effects the vertical adjustment of the folder block in response to the imbalances in an air bridge monitor of the rod diameter.

BRIEF SUMMARY OF THE INVENTION This invention relates to a continuous rod-forming machine such as form cigarette rods or filter rods. More particularly, it relates to a method and a means for continuously controlling the diameter of such rods as they are formed.

It is an object of the invention to instantaneously and continuously detect variations in rod diameter at a point adjacent the folder block and to adjust the height of the folder block in direct response to stimuli or signals from such measurements.

It is a further object of the invention to control the diameter of a cigarette or filter rod by continuously adjusting the elevation of the folder block in direct response to variations in the diameter of the rod being formed.

It is a particular object of the invention to detect rod diameter by a fluid comparison amplifier whose output directly varies the elevation of the folder .block.

In carrying out the invention the diameter of the rod is monitored by its throttling effect as it passes through an orifice formed in one leg of a balanced air bridge. Resultant imbalance in the bridge is amplified to directly controlthe elevation of the folder block. The folder block has a cantilever spring configuration urging its operative end in one direction, preferably downward.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS 6 OF THE DRAWINGS A rod-forming apparatus according to the invention is shown in the accompanying drawings in which:

FIG. 1 is a side elevation of the garniture section of a cigarette machine;

FIG. 2 is an enlarged perspective view of the same;

FIG. 3 is a schematic illustration showing one method of controlling the folder block in a rod-forming machine;

FIG. 4 is a schematic illustration of another embodiment for controlling the folder block;

FIG. 5 is a fragmentary showing of the folder block;

FIG. 6 is a cross section of the folder block taken on the line 6--6 of FIG. 5.

DETAILED DESCRIPTION In the drawings, the rod-forming section 10 of the rodforming section 10 of the rod-making machine has a ice folder belt 12 supporting the continuous paper wrapper 14 whose edges are turned up to form a trough in which the tobacco lies. The margin 16 (FIG. 2) of the paper is higher than the opposite margin 18 and receives adhesive from a paster wheel 20 prior to its entering the shaped channel 22 of the folder block 24. Folder block 24 is secured at its center to the bed 29 of the machine by the screw 26 to give it a spring cantilever construction allowing right end 28 to be raised in springboard fashion. A pair of screws 27 are threaded into holes in the left end of the folder block. The lower ends of the screws 27 engage the bed 29. By adjusting the screws 27, the spring rate of the folder block may be varied.

As the wrapper 14 moves through the folder block, the margin 16 is guided so that it overlaps the margin 18, and the two margins are held together while the adhesive is bonded by the action of a heated sealer 19. By raising and lowering the entering end 28 of the folder block 24, the amount of overlap of margins 16 and 18, and hence the diameter of the finished rod, may be controlled.

The folder block 24 is recessed as shown at 24a to accommodate the sealer 19. Since the point where the folder block 24 is attached to the bed of the apparatus by the screw 26 is spaced from the right hand end of the block, it may be seen that the right hand or entrance portion of the folder block 24 is raised and lowered by the operation of the motor mechanism to be described. The groove 22 on the under side of the block 24 extends over the cigarette rod only as far back as the recess 24a. The portion of the folder block located beyond the recess 24a dOes not extend over the cigarette rod.

A sensing head 30 positioned at the output end of the folder block consists of a tube 32 (FIG. 3) through which the formed rod 34 passes. Tube 32 has an annular chamber 31 communicating with bore 33 through radial orifices 35. The rod 34 forms with the tube 32 a throttled aperture whose cross-sectional area changes with variations in rod diameter.

Supply input conduit 36 connected to a regulated source of air (not shown) communicates directly with the supply port 38 of a proportional fluid amplifier 39. The fluid amplifier 39 may consist of a single proportional amplifier stage or it may consist of a plurality of cascaded stages, as is well known in the art. Also in communication with the conduit 36 is the throttled sensing tube 40 having a throttle 42. Tube 32 of the sensing head communicates by means of a tube 44 with throttled-down portion 40a of tube 40. A throttled tube 46 having a throttle 48 has a throttled-down portion 46a in communication with the ambient through a balancing valve 50' whose orifice 52 may be controlled by the adjustable valve cone 54. One input tube 56 of the fluid amplifier 39 is inserted into the throttled-down portion 40a and communicates with it through a number of peripheral orifices 58. In like fashion, the other input tube 60 is inserted into and communicates with throttled-down portion 46a through a plurality of openings 62.

The output tubes 64, 66 of the fluid amplifier 39 communicate respectively with the bellows 68, 70* which are connected by a T-member 72 to each. other and to the free end of the lever 74. Lever 74 is pivoted at 76 and its other end is pivotally connected to a control rod 78 secured at its distal end to the free end 28 of folder block 24. The bellows 68, 70 constitute dead loads on the fluid amplifier 39, in that the bellows are not vented and hence cannot accommodate a flow. Hence, the fluid amplifier 39 must be of the internally vented, load insensitive type, in order to drive the dead load bellows 68 and 70.

As may be seen by reference to FIG. 3, the eifective opening in the orifice 52 may be throttled by a cone 54 until the throttled portions 40a and 46a are equal for the desired diameter of the rod 34. Thus, each position of valve 50 corresponds to a predetermined rod diameter.

Should the diameter of the rod 34 increase it will have an additional throttling action on air passing out of the passage between the tube 32 and the rod 34. This will result in an increase in pressure in the throttled portion 40a and consequently in the input tube 56. This will divert the air supply in the proportional fluid amplifier 39 so that there will be an increase in pressure (flow) in the output tube 66 and a corresponding decrease in the output tube 64. The bellows 70 will thus expand while the bellows 68 contracts causing the rod 78 to move in the direction of the arrow F in FIG. 3. This movement will depress the free end of spring cantilever folder block 28 toward the center of the rod to reduce the diameter of the rod until equilibrium is again established.

In the modification shown in FIG. 4 the output duct 64 communicates with one end of a reversible fluid motor 80 while the output duct 66 communicates with the other end of the motor. The motor output shaft 82 is coupled to a leadscrew 84 rotatably but non-slidably mounted in plate I86 and threadedly engaged in the free end 28 of folder block 24. The motor 80 is so constructed that 'when tube 64 is at the higher flow pressure level than 66, output shaft 82 rotates clockwise viewed from above to raise free end 28 of folder block 24. Conversely, when 66 is at the higher level, shaft 82 rotates counterclockwise to lower free end 28.

The control system illustrated in FIG. 3 may be termed a proportional control system. The bellows 68 and 70 have inherent spring rates, and tend to assume a balanced position in the absence of (1) any pressure difference between their internal pressures, and (2) any external 4 load. Since the folder block 24 is a spring element, it biases the left end of lever 74 upwardly, constituting an external load on the bellows 68 and 70, and establishing the normal position of the T-member 72, i.e., the position corresponding to the median position of folder block 24, somewhat above the balanced position described above. The valve 50 may be set so that the pressure in bellows 68 is sufficiently greater than the pressure in bellows 70 to hold the folder block in that median position.

After that median position has been established, the cigarette rod 34 becomes larger and hence increasingly restricts the flow in the sensing head 30, the pressure in the bellows 68 is decreased and the pressure in the bellows 70 is increased. This raises the left end of lever 74 and lowers the folder block 24, decreasing the diameter of the cigarette rod. This movement of the folder block 24 continues until the pressure difference between the two bellows is again balanced by the inherent spring rates of the two bellows, and that of the folder block.

It may be seen that the movement of the T-connection 72 in either direction from its normal position requires the application and maintenance of a force acting either upwardly or downwardly. Hence, in this system, for any given setting of the valve 50, and for any given restriction at the sensing head 30, there is a particular position of the folder block 24 which will cause the system to be stably balanced. A particular setting of valve 50 thus determines the diameter of the cigarette rod.

In the system of FIG. 4, the position of the folder block 28 is independent of any forces acting on the rotary fluid motor 80. This system always operates the fluid motor in one direction or the other until the pressure losses at the sensing head 30 and the valve 50 are equal so that the pressure supplied through the conduits 64 and 66 are equal. Hence, the folder block 24 may assume any position within its range of movement as long as that position will maintain the two pressures balanced. This may be termed a floating control system, as opposed to the proportional control system of FIG. 3. Nevertheless, in this system also, a setting of the valve 50 determines the diameter of the cigarette rod. V

I claim:

1. In a continuous rod-forming device having a folder block, adjustable means supporting said folder block for adjustment toward and away from the axis of said rod, a fluid-flow sensing instrumentality operatively positioned near said folder block and constructed and arranged to sense a change in diameter of said continuously moving rod, a conduit to conduct a continuous flow of fluid to said sensing instrumentality, a fluid amplifier connected to said conduit and to said fluid-flow sensing instrumentality, a' fluid actuated mechanism mechanically connected to said adjustable means and connected to said fluid amplifier so that variations in the diameter of said rod produces compensating variations in the adjustable position of said folder block whereby said folder block is moved toward said axis in response to an increase in diameter of said rod and away from said axis in response to a decrease in diameter of said rod.

2. A device substantially as set forth in claim 1 in which said folder block is secured at one end and said adjustable supporting means support its other end.

3. A device substantially as set forth in claim 1 further characterized in that said fluid sensing instrumentality comprises a balanced air bridge having one leg in communication with a tube surrounding and spaced from said rod.

4. A device substantially as set forth in claim 3 in which said balanced air bridge has another leg, and further characterized in that an adjustable valve is positioned in the other leg of said balanced bridge, said valve communicating said other leg with the ambient.

5. A device substantially as set forth in claim 1 and further characterized in that said fluid actuated mechanism comprises an expansible chamber having a movable wall.

6. A device substantially as set forth in claim 1 and further characterized in that said fluid actuated mechanism comprises a reversible pneumatic motor.

7. Apparatus for controlling the diameter of a cigarette rod, comprising:

(a) means for advancing a troughed paper strip with tobacco in the trough and the margins of the troughed strip directed upwardly, at least one of said margins being coated with adhesive material;

(b) a block of resilient material extending alongside the path of the paper strip and fixed in position only at the end of the block farthest along the path of movement of the strip;

(c) a folder projection extending from said block over the path of movement of the strip, said projection having a groove in its under side contoured to guide one margin of the strip into contact with the other margin and to hold them in adhesive contact;

wherein the improvement comprises:

(d) mechanical means for raising and lowering the free end of the folder block;

(e) pneumatic motor means mechanically connected to said mechanical means;

(f) fluid amplifier means for controlling the pneumatic motor means;

(g) balanced air bridge means controlling said fluid amplifier means, said balanced air bridge means including:

(h) a manually adjustable valve in one side of the bridge; and

(i) a sensing head for receiving the cigarette rod leaving the folder block and controlling the pressure in the other side of the balanced air bridge in accordance with the diameter of that rod.

(References on following page) 5 6 References Cited 3,380,351 4/1968 COX et a1.

Dexter X 10/1902 Ludington 131 68 SAMUEL KQREN, Primary Examiner 5 1927 i Ianni 131 5 J. H. CZERWONKY, Assistant Examiner 2/ 1954 Berriman 131--20 U.S. C1. X.R. 11/1966 Moline et a1. 

